trailer wiring

I have a '99 suburban that was leased and never set up for trailer wiring. I found the 4 wire harness behind the bumper. I do not see the wiring for the electrical brakes to the plug. Also is there a harness for the controller under the dash. My dealer seems ignorant.

up in the back of the vehical drivers side its hidden well you will find two wires a blue and an orange constant power orange. blue is for trailer brakes.
under your hood u will find the same wires wrapped tucked beside/below your brake booster.
you will need to hard wire your trailer brake controll ..

by the way your brake wire (switch) that u need to
up to ur controller (hot) side is the white wire under ur dash...

Gawd there must be 15 white wires up under there, all bundled differently and going off in umpteen different directions. I'm about at wits end with mine and all I have to do is wire the brake controller wire to the cold side of the Stoplight switch.

GM must have hired Little People to wire this thing as I can't get anywhere under the dash.

Any ideas on a wire closer to the fuse panel or surface??

I'm having this same issue. I have a 7 pin connector at the bumper and a 6 pin on the trailer. I bought the wire adapter for the brake controler that plugs directly into the fuse block under the dash. Everything works fine except for the elec brakes. I took the truck to a place that installs brake controllers to let them figure it out and all it did then was lock up the brakes when I steped on the brake. No matter which way I moved the adjustment wheels on the controler they still locked up and the controller always showed an open circut (--). I may have to look for the wires under the brake booster and try that....

Just wanted to let you know your not the only one with this issue....:banghead:

I found the one I needed. Here's the link......http://www.automotiveforums.com/vbulletin/showthread.php?p=2294871